Lachey was a celebrity dancer on the second season of Dancing with the Stars with professional dance partner Cheryl Burke. At the beginning of the sixth week of competition (aired in February 2006), Lachey and Burke earned a perfect score of 30 with their tango. In the eighth and final week, they earned a score of 30 on each of their two dances, the Paso Doble and freestyle, giving them the highest score for the week. On February 26, 2006, they were crowned the champions of Dancing with the Stars.

From December 2006 to February 2007, Drew toured both Canada and the United States for the Dancing with the Stars Tour. On the April 17, 2007 results show, Lachey made a surprise appearance to reprise his "Save a Horse (Ride a Cowboy)" freestyle dance with Cheryl Burke. He co-hosted the first 3 weeks of the fifth season of Dancing with the Stars, temporarily replacing Samantha Harris during her maternity leave. He also stepped in for Tom for one episode.When Gloria Estefan had to pull out of the October 16, 2007 results show for personal reasons, Lachey returned to dance a foxtrot with Cheryl. After the show, Drew and Cheryl were rumored to have been having an affair. Both denied this story.

Lachey was also presenter of HGTV's spring 2009 series the reality show where five neighboring families competed for the chance to win $250,000 to pay off their mortgage by competing in home-improvement challenges.

Drew and design partner Sabrina Soto won the celebrity edition of HGTV's Showdown, "Battle of the Bonus Room" shown in July, 2009. The team beat designer Matthew Finlason and celebrity, Kristi Yamaguchi.

Lachey returned to Dancing with the Stars in its fifteenth season as one of the "All-Stars" contestants.[2] This time he was partnered with Anna Trebunskaya.[3] They were the third couple eliminated from the competition.

Lachey married Lea Lachey on October 14, 2000. They were childhood and high-school sweethearts, and she was the choreographer for 98 Degrees, as well as one of the dancers. Their first child, daughter Isabella Claire Lachey, was born on March 23, 2006 in Los Angeles, California, weighing 7 lb 2 oz (3.2 kg). On December 14, 2009, it was announced that the couple was expecting their second child, a boy, due in Spring 2010.[4] Their second child, son Hudson Nicholas Lachey, was born on May 15, 2010 in Cincinnati, Ohio.[5] The two of them also run a Cincinnati-area performing arts day camp.[6]